The part we used was Sprague-Goodman GCL40000 (now obsolete). These are 1-40 pF with a very low temperature coefficient.
Trimmers still available have TCs that are 2 to 4 times worse, and have a higher minimum C. These are fine for applications where small drifts in C with temperature don't significantly alter the passband of the filter (e.g., in the KFL1-2, K2, and K3). But the KFL1-4 requires very high-Q filters in order to remove mixing products from both the pre-mixer and transmit mixer stages. The low minimum-C is needed for the higher-band filters. We found that if we used trimmers with a worse TC on the KFL1-4, then power output would temporarily drop (in some cases by 50-70%) when the K1 was operated at an ambient temperature quite different from that at time of alignment. That would be unacceptable for a rig often used outdoors. 73, Wayne N6KR On Mar 7, 2015, at 8:06 AM, "Wes (N7WS)" <w...@triconet.org> wrote: > On 3/6/2015 9:33 PM, Don Wilhelm wrote: >> The part number for the bare KFL1-4 board is E100129 as listed in the KFL1-4 >> manual. > > Is there a commercial P/N specified for the capacitors? > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to n...@elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
